1. Heat sealing temperature: Heat sealing temperature directly affects the heat sealing strength of the packaging film.
2. Heat sealing time: The heat sealing time of an automatic packaging machine or an old-fashioned bag making machine is determined by the machine speed. When the heat sealing temperature and heat sealing pressure remain unchanged, the longer the heat sealing time, the stronger the bond between the heat sealing layers. However, if the heat sealing time is too long, wrinkles and unevenness will appear in the heat-sealed parts of the packaging film, seriously affecting the appearance quality of the product.
3. Heat sealing pressure: In order to ensure the heat sealing strength of the packaging film, corresponding heat sealing pressure is needed. Therefore, the heat sealing pressure is required to be moderate and uniform during the heat sealing process. If the heat sealing pressure is insufficient or uneven, bubbles will be generated in the heat sealing area, resulting in poor heat sealing.